The present disclosure is directed to systems and methods for tracking interventional or implantable medical devices using medical imaging systems. More particularly, the disclosure relates to a system and method for visualizing medical devices during an implantation or interventional procedure, for example, as the medical devices are adjusted and changed during the procedure.
Image-based guidance of therapeutic devices, such as catheters, and/or the placement of interventional devices, such as guidewires and stents is a key component of modern medicine. Currently, x-ray fluoroscopy is the gold standard for such image-guided procedures. For example, the tips of guidewires can be easily visualized using conventional x-ray fluoroscopy by applying small, radio-opaque markers to the tips.
However, as the device becomes more complex and/or the surrounding tissue exerts greater influence on a system, it can be difficult to communicate the desired information to a clinician. For example, guiding and placing an expandable stent within a vessel can be difficult using traditional methods of visualization using x-ray fluoroscopy because the stent, itself, is a three-dimensional object, can move in three-dimensions, and can deform in various directions during movement or deployment when interacting with surrounding tissue. Thus, it can be very difficult for a clinician to accurately understand the orientation and deployment position of the stent in three dimensions from a two-dimensional, fluoroscopic image.
Transcatheter aortic valve replacement (TAVR) has been developed as a less-invasive treatment option for patients with severe aortic valve stenosis who are high risk for open chest surgery. In this fluoroscopically-guided procedure, a balloon-expandable stent-supported tissue valve is carefully positioned in the left ventricular outflow tract at the level of the aortic annulus. The balloon is expanded to deploy the valve. Accurate device visualization relative to the target anatomy is both highly challenging and critical to procedure success.
Conventional x-ray fluoroscopic imaging only provides a 2D view of a 3D device, leading to ambiguities in the position and orientation of the device. Continuous high frame rate 3D CT scanning of the device in the interventional catheter laboratory is not practical and the radiation dose to the patient would prohibit its use for visualization during such a procedure. Back-projection reconstruction from 2 simultaneous bi-plane views may be suitable for very simple devices such as a curvilinear guidewire or catheter body, but for complex devices that are self-overlapping in the measured x-ray views, such as a TAVR valve, these traditional imaging processes fail.
Accordingly, multimodal image fusion has gained interest, particularly for cardiac interventional procedures. For example, catheter detection and tracking using fluoroscopy can provide motion compensation of anatomical roadmaps used to help guide electrophysiology procedures, such as described in Brost, Alexander, et al. “Respiratory motion compensation by model-based catheter tracking during EP procedures.” Medical Image Analysis 14.5 (2010): 695-706. To provide the clinician with more information in structural heart interventions, transesophageal echo (TEE) has been registered with x-ray fluoroscopic (XRF) images. This TEE/XRF registration allows anatomical information from echo to be combined with device imaging from XRF and help the clinician to better understand the position and deployment condition of a complex device, such as an expandable stent or the like. However, these registration systems do not provide an XRF-based 3D representation of the device registered to TEE, making it difficult to fully appreciate the device status relative to patient anatomy.
Therefore, it would be desirable to have new systems and methods that enable a clinician to track and understand the position and movement of interventional and/or implantable medical devices during an interventional procedure.